Signaling system



Aug. 17, 1943.

B. F. LEWIS SIGNALING SYSTEM Filed.Aug. 28, 1941 ATTORNEY Patented Aug. 17, 1943 UNITED STATE-.s PATENT f'oFFrcE f SIGNALING SYSTEM Y n v Benjamin F. Lewis, BaysidajN. Y., Vassigner toV Bell Telephone Laboratories, Incorporated, New Y'York, N. Y., a corporation of New York f Application August 28, 1941, Serial No. 408,597

5 claims. (01.179-16) This invention relates to signaling systems and particularlyV to means for controling communication system switching devices. Y Y v For many years communication system switching devices have operated on'a decimal basis in response to digital trains of pulses. Recently, in an effort to reduce the time consumed in transmitting signals from subscriber premises, a system based on permutation code signals has been developed. This system employs asubscriber controlledattenuating currentJ generator comprising essentially a magnetic circuit interlinked with an electrical circuit with a plurality of reeds each of a different natural period of vibration and means to selectively pluck said reeds whereby the magnetic circuit is aiected and alternating currents of correspondinglyrdiiferent frequencies are produced in said electrical circuit-for transmission over the line. The time for sending the different digital impulses is thus very brief and uniform in every case. Thereby an improved system is produced in that the timeconsumed by the'subscriber` in dialing is greatly'reduced.

As these new systems are installed there will of necessity be aninterim period during which both the old and the new systems are inY operation and translating devices will have to be employed-devices which will respond to the new substation apparatus for controlling the old type switching apparatus. Devices of this general nature have heretofore been devised but they have so far been of a complicated and expensive nature.

The object of the present invention is to previde a translator for thispurpose of asimple and economical nature. Accordingly, a well-known mechanical pulse regenerator has been used as a basis for transmitting digital trains of pulses and has been Vmodified by'lmaking it responsive to incoming signals in the form of coded alternating current signals. 1 f

A feature of the invention is a pawl and ratchet wheel combination in which the pawl may be moved over avariable number ofteeth of the ratchet wheel in response tovariable incoming signals of the coded attenuating current type, the variable number of teeth advanced correspending to the variable lengthtrains of pulses OtherA features will appear in the following description. Y i' The drawing vis a single sheet having a single ligure showing the invention in schematic form. A telephone substation and line are shown in schematic circuit diagram, an alternating current responsive device is indicated, the mechanism embodying the novelV features of the invention is shown in a perspective view also in schematic form and the pulse generating unit operated by the said mechanism is indicated by abox.

`A telephone or other substation in a signaling system is indicated by the rectangle l, and contains the twoessential elements a substation set 2 fcrcommunication purposes and an alternating current generator 3 capable of sending out alternating currents of several different distinct frequencies. A pairof lines 4f and E extend to adistant point and by being broken'at several pointsindicate lengthV and the'usual circuit arrangements employedin switching operations. A pair of wires 6 andl lead from the signaling channelprovided by the wires 4 and 5 to an alternatingcurrent responsivedevice 8. This device is well known and operates to translate signals sent by the generator 3 into digital signals. Such a device is disclosed in Patent No. 22015296 grantedMay 2l, 1940, to A. A. Lundstrom and E. L. Norton. The usual arrangement is to provide a generator 3 which will transmit five different frequencies and to operate this generator by a reed'plucking mechanism by which ten differ-` ent combinations of two different-frequencies are simultaneously transmitted. These ten diiferent signals will operate the device 8 to affect a common wire 9 and a selected one of the leads l0 as clearly shown in the above-noted LundstromV etV al. patent.

Upon the receipt-of a signal transmitted from the station l, therefore, the wire 9 will lbe grounded to operate the'relay 2l and a selected one of theV wires I0 will be grounded to operate a corresponding one ofthe solenoids il to 2t!- inclusive. Y

These solenoids operate on a lever arm 2?., pivoted 4at 23 and provided with a pawl 25. at its oppositeY end. Y The' pawlV 24 cooperates with a ratchet Wheel 25 and the arrangement is such that cach solenoid will advance the pawl 2li over a different number of teeth of the ratchet wheel 25.' If the solenoid Il is operated then the pawl 24 will advance over only a singletcoth of the wheel 25. If'the solenoid '2G is operated then the pawl 24 will advance overl() teeth of the ratchet wheel '25. The last digit ofthe number indicating each of said solenoids indicates the number of teeth over which the said pawl will advance. Appropriate slots for the plungers of the different solenoids are formed. in the vanev The ratchet Wheel 25, the marking or 'pinsetting magnet 24, its armature 30 and the box 3| represent in schematic form a mechanical impulse repeater according to the disclosure in Patent No. 2,188,461, granted January 30, 1940, to John William McClew and Cecil Robert Woodland, which device is commonly known as the English type regenerator.

Generally stated, the operation of this device involves the steady operation of the marker or pin setting magnet 29 whereby a collar 32 on a shaft 33 is pushed in while the ratchet wheel 25 is being set.v When the ratchet wheel 25 is fully set then the armature 30 is retracted, the collar 32 is released to its normal position and a selected pin in the device 3| is set after which the device operates to send out a train of pulses over the Wires 34 and 35 corresponding in number to the distance the ratchet wheel 25 has been moved. Thus a signal is sent from the station I in the form of a combination of two selected frequencies oi alternating current which is translated by the arrangement here disclosed into a corresponding digital train of direct current pulses.

Upon the operation of the generator 3, therefore, the conductor 9 is grounded, resulting in the operation of relayl 2| whereupon the marker magnet 29 is operated.. At the same time a selected one of the solenoids to is operated and the lever comprising the two armsV 22 and 21 is rotated a correspondingdistance in a counterclockwise direction. The off normal contacts 36 and 31 close to maintain the relay 2| operated. In a very short time, since the operation of the generator 3 is only transitory the ground connection to conductor 9 and the selected o-ne of the conductors I0 is removed. The spring 25 returns the lever comprising the arms 22 and 21 to normal and thereby rotates the ratchet wheel V2li a predetermined distance. When such normal position has been reached the circuit through the oir normal springs and 31 is opened with the result that relay 2| and then magnet 29 are released, resulting in the setting of the device 3| which thereupon operates as fully described in the ,above-noted McClew et al patent.

The break in the conductors 4 and 5 between the point where the conductors 8 and 1 and the pointI where the conductors 34 and 35 represent the usual circuit arrangements for preventing interference between the incoming alternating current signals and the outgoing digital trains of direct current pulses.

What is claimed is:

1. In a signaling system a line, a signal transmitter at one end of said liney said transmitter comprising means to send digital rsignals the elements of each signal being transmitted simultaneously, signal controlled means'at the other end of said lineV comprising means responsive to digital signals, each said signal comprising a train of sequentially arranged impulses, and a translator in said line for changing said iirst type of signals to corresponding numerical trains of impulses, said translator comprising a plurality of magnets each responsive to a diierent incoming signal, a pivoted bar, lost motion connections between said magnets and said bar whereby each said magnet may move said bar through a correspondingly diierent aro, a pawl controlled by said bar and a transmitter for sending trains of sequentially arranged impulses having a ratchet wheel controlled by said pawl.

2. In a signaling system, a line, a signal transmitter at one end of said line, said transmitter comprising an alternating current generator arranged to produce a plurality of different alternating current signals and means for operating said generator to transmit said signals in a permutation code, the elements of each said permutation code being simultaneously transmitted, step-by-step apparatus at the other end of said line-responsive to numerical trains of direct current pulses sequentially transmitted and a translator in said lines responsive to said coded alternating current signals for changing said signals into corresponding numercial trains of direct current signals, said translator comprising a plurality of magnets each responsive to a different incoming signal, a pivoted bar, lost motion connections between said magnets and said bar whereby each said magnet may move said bar through a correspondingly dif- V ferent arc, a pawl controlled by said bar and a transmitter for sending trains of sequentially arranged impulses having a ratchet wheel controlled by said pawl.

3. In a signaling system, a line, a signal transmitter at-one end of said line, said transmitter comprising an alternating current generator arranged to produce a plurality of 'different alternating current signals and means for .operating said generator to transmitv said signals in a permutation code, the elements of each said permutation code being simultaneously transmitted, step-by-step apparatus at the other end of said line responsive to numerical trains of direct current pulses sequentially transmitted and a translator in said lines responsive to said coded alternating current signals for changing said signals into corresponding numerical trains of direct current signals, said translator comprising a step-by-step device operated by a pawl and ratchet wheel and means responsive to different 1incoming coded alternating current signals for advancing said pawl in a single stroke over the saidteeth of said ratchet wheel, a number of teeth corresponding to thev number of pulses to be transmitted by said translator.

4. Inra signaling system, a line, a signal transmitter at one end of said line, said transmitter comprising an alternating current generator arranged to produce a plurality of different alternating current signals and means for operating said generator to simultaneously transmit the elements of said signals in a permutation code, step-by-step apparatus at the other end of said line responsive to numerical trains of directeurrent pulses sequentially transmitted and a translator in said lines responsive to said coded alternating current signals for changing said signals into corresponding numerical trains of direct current signals, said translator comprising a step-bystep device operated by a pawl and ratchet wheel combination, a plurality of magnets for moving said pawl each said magnet advancing said pawl in a single stroke a dii-ferent number of teeth over said ratchet wheel and means responsive to said incoming coded alternating current s ignals for selectively operating said magnets.

5. A mechanical arrangement for translating simultaneously transmitted permutation coded alternating currentV signals into sequentially transmitted trains of direct current signals, comprising a plurality of magnets each responsive 

